Booth SL., et al.: Dietary vitamin K intakes are associated with hip fracture but not with bone mineral density in elderly men and women.American Journal of Clinical Nutrition, May 2000 71(5): 1201-1208.

Kaneki M., et al.: Japanese Fermented Soybean Food as the Major Determinant of the Large Geograpfhic Difference in Circulating Levels of Vitamin K2: Possible Implications for Hip-Fracture Risk.Nutrition, 2001 17(4): 315-321.